I think the DCs are sorted (thanks to Pres for helping me test), turns out that even if you allow BB for both incoming and outgoing traffic in Zone Alarm it'll still mess you about. I'll just quit it altogether in future, hopefully that'll do the trick.
The crashes aren't BB specifically, damned if I know what it is but about once a month or so my computer will BSOD (7f or 1e), making it impossible to track down. It's happened in BB, Stellar Impact and just randomly on the desktop. I've tried removing the overclock, reseating the RAM and tweaking voltages but nothing's helped so far unfortunately.
Screwie - Turn 5 is kinda early, but this was my third DC'd game in the last week or so. Thinking back to the DC on our game on the last turn, and how happy I was that that turned a 2-0 win into a 2-0 loss, I offered PW an admin win instead of a replay. Nuffle giveth, and Nuffle taketh away.